Astrophysicists at UC Santa Barbara are the first scientists to identify two white dwarf stars in an eclipsing binary system, allowing for the first direct radius measurement of a rare white dwarf composed of pure helium.

An international team led by Yale University has, for the first time, measured the mass of a type of supernova thought to belong to a unique subclass and confirmed that it surpasses what was believed to be an upper mass limit.

New findings from NASA's Chandra X-ray Observatory have provided a major advance in understanding a type of supernova critical for studying the dark energy that astronomers think pervades the universe.

WASHINGTON, Feb 17 /PRNewswire-USNewswire/ -- New findings from NASA's Chandra X-ray Observatory have provided a major advance in understanding a type of supernova critical for studying the dark energy that astronomers think pervades the universe.

An extraordinarily bright, extraordinarily long-lasting supernova named SN 2007bi, snagged in a search by a robotic telescope, turns out to be the first example of the kind of stars that first populated the Universe.

Using ESOâ€™s Very Large Telescope and its ability to obtain images as sharp as if taken from space, astronomers have made the first time-lapse movie of a rather unusual shell ejected by a â€œvampire starâ€, which in November 2000 underwent an outburst after gulping down part of its companionâ€™s matter.

White Dwarf -- A white dwarf is a a star supported by electron degeneracy. A star like our Sun will become a white dwarf when it has exhausted its nuclear fuel.
Near the end of its nuclear burning stage, such a star goes through a red giant phase and then expels most of its outer material (creating a planetary nebula) until only the hot (T > 100,000 K) core remains, which then settles down to become a young white dwarf.
A typical white dwarf is half as massive as the Sun, yet only...

Stellar Evolution -- Stellar evolution is the process of formation, life, and death of stars. It is one of the major topics of cosmogony.
Star Birth and Life
A star starts out as an enormous cloud of gas and dust many light-years across. Star formation begins when the cloud begins to condense under its own gravity. The processes that initiate this contraction are not fully understood. The cloud fragments fuse into stellar mass clouds known as protostars. Protostars do not emit...

Nova -- A nova is an enormous nuclear explosion caused by the accretion of hydrogen onto the surface of a white dwarf star.
When a white dwarf has a close companion star, the companion will often begin to have its outer atmosphere drawn away from it by the white dwarf's gravity as the companion star ages and expands into a red giant.
The gases so captured consist primarily of hydrogen and helium, the two principle constituents of matter in the universe. The gases are compacted on the...

Cataclysmic Variable Star -- Cataclysmic variables are a class of binary stars containing a white dwarf and a companion star. The companion star is usually a red dwarf, although in some cases it is another white dwarf or a slightly evolved star (subgiant). Several hundreds of cataclysmic variables are known.
From the observational viewpoint, cataclysmic variables are relatively easy to discover. They are usually quite blue objects, as the majority of stars are red. The variability of...

Sirius -- Sirius (Î± Canis Major, also known as the Dog Star) is the brightest star (-1.46m) in the night sky and can be seen from every inhabited region of the Earth's surface.
At a distance of 8.6 light years, Sirius is also one of the nearest stars to Earth. It is a main sequence star of spectral type A0 or A1 and has a mass about 2.4 times that of the Sun.
Sirius has a white dwarf companion called Sirius B which orbits it with a period close to 50 years. It was the first white...

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